Sydney's North Shore suburb-gardens, steep sandstone gullies, and railway line edges from Sydney and Strathfield northwards are to some extent infested by original big Camphors, total-canopy with few if any natives remaining, or the 'next wave' of 5-15 year old 'hybrid' Camphors invading since the first El-nino drought of the early to late 1980s; Camphors appear suited to surviving drought/s and extended dry periods, possibly taking water as light rain or mist etc through leaf stomata/glands.
Large old Camphors' in the inner suburbs of Sydney are likely to be 'less-toxic' or of original 'Chinese '(l828) introduction from Kew (London), or their direct offspring (prior to 1881), since east Asian texts, and Donkin (1999) state that these trees can/have lived for up to 300 years! Less-toxic chemotypes may predominate in Sydney, and the near-coastal strip of NSW, if and where 'not stressed' by over 39-40 degrees C summer daytime temperatures. However, more-toxic types have been collected in various suburbs of outer Sydney, Newcastle, and most towns from Taree northwards.
NSW's Northern Rivers' region represents by far the worst, and largest invasion of Camphors in all Australia, now slowly invading westwards (Mapping by satellite in-prep.) from the densest infestations in northeast Lismore Shire, and northwest Byron Shire, as well as the south and east ends of Tweed Shire. Most of the original large, old Camphors have already been cut, removed and killed on farms and public places where they grew to up to 3 ms diameter (Bellinger, Brunswick, Richmond & Tweed Rivers) from 1870 to 1980 - av. Ca. 110 years old i.e. expanding annually up to 3 cm per year.
The active selection of the biggest old Camphors for slabbing, and furniture-making since the 1940s in northern NSW, has resulted in general in the remaining population of Camphor laurels being of lesser stature, growing in more dense stands, and being 'more-toxic' types (=chemotypes) by and large - since the timber industry , and consumers do not favour cut-timber types with non-homogeneous grain, especially the high safrole type/s with dark brown and/or streaky heartwood centres.
Invasive spread of Camphors' first noted in The Northern Star (Lismore, 1900) as being a 'westward' push, due to bird-seed drop or vomiting, being especially more likely to be vomited if and where birds (Currawong, Crow, Magpie , Pigeons etc) have consumed more-toxic types in hot weather, is now at its worst in the drier, brush rainforest country of the upper Clarence valley e.g. Bonalbo, Tooloom, Woodenbong and other localities, bird-moved out from heavy-seeding farm and schoolyard Camphors in and around various towns and smaller villages.
Planted Camphor trees are known (sampled) to have commenced viable-seeding through the record drought of 2001-2003, at over 1000 ms elevation at both Tenterfield and Uralla, on the main range of NSW's Northern Tablelands.
Western-spread and seeding is known from collections (2003) at Tamworth and Dubbo (Central-West Region)Northward and eastward invasion/spread of Camphor trees includes in-rainforest specimens at over 550ms elevation in short-montagne mist forest on the NSW-Queensland border, as well as into the sand-dune/hind-dune parts of Byron and Tweed shire beaches. Invasion of islands of river estuaries, generally ensures that these weeds are never or rarely controlled (by pulling or thinning/poisoning).